[MrB]

Without checking it out for myself, I’ll tell you how to do it -

an octave is a doubling of frequency.

So take the frequency of the “middle B flat” and double it 40 times (times 2 to the 40th power) and compare that to the frequency of yellow.

[Maceman]

Without checking it out for myself, I’ll tell you how to do it - an octave is a doubling of frequency. So take the frequency of the “middle B flat” and double it 40 times (times 2 to the 40th power) and compare that to the frequency of yellow.

Of course you are correct. But at the time the comment was made, nobody -- including myself -- felt like doing the math, nor looking up the frequency of yellow. It's been 34 years since that class, so maybe I'll get around to doing it now. (Probably not though.)